IL-4-Induced Gene 1: A Potential Player in Myocardial Infarction.

Myocardial infarction (MI), a severe outcome of cardiovascular disease, poses a serious threat to human health. Uncontrolled inflammation and excessive cardiomyocyte death, following an infarction event, significantly contribute to both the mortality rate and complications associated with MI. The protein IL-4-induced gene 1 (IL4I1 or FIG1) serves as a natural inhibitor of innate and adaptive immunity, playing a crucial role in CD4+ T cell differentiation, macrophage polarization, and ferroptosis inhibition. Previous studies have linked IL4I1 to acute MI. This review summarizes evidence from both basic and clinical research, highlighting IL4I1 as a critical immunoregulatory enzyme that not only regulates inflammatory responses, but also potentially mitigates MI-induced damage.

Adenoviral fiber-knob based vaccination elicits efficient neutralizing antibodies and T cell responses against adenovirus infection.

BACKGROUND: Human adenoviruses (HAdVs) frequently cause common respiratory or gastrointestinal infections among children, adults, individuals with immune deficiencies, and other vulnerable populations with varying degree of symptoms, ranging from mild to server, and in some cases, even fatalities. Despite the significant clinical impact of HAdVs, there is currently no approved vaccine available. METHODS: This study explores the potential of the adenovirus type 5 fiber knob (Ad5-FK) to stimulate the production of Ad-specific neutralizing antibodies and T-cell responses in mice. Based on structure predictions, we first expressed Ad5-FK in E. coli and confirmed the assembly of FK into its trimeric form. After testing the binding capability of the trimeric FK to susceptible cells, the immunogenicity of the protein in combination with the c-di-AMP adjuvant was assessed in BALB/c mice. RESULTS: The purified Ad5-FK exhibited self-trimerization and maintained correct conformation akin to the authentic FK structure. This facilitated effective binding to susceptible HEK293 cells. Notably, the protein demonstrated significant inhibition of HEK293 cells infection by rAd5-GFP. Immunization of BALB/c mice with Ad5-FK, or Ad5-FK mixed with c-di-AMP yielded FK-specific antibodies with potent neutralization capacity. Significantly, Ad5-FK was found to elicit a vigorous CD4+ T-cell response in the immunized mice. CONCLUSION: Our findings underscore the efficacy of FK-based vaccine in eliciting anti-Ad humoral immune response and CD4 T-cell immune reactions essential for protection against viral infections.

UFMylation is involved in serum inflammatory cytokines generation and splenic T cell activation induced by lipopolysaccharide.

UFMylation, a novel ubiquitin-like protein modification system, has been recently found to be activated in inflammation. However, the effects of UFMylation activation on inflammation in vivo remains unclear. In the present study, we generated a UFMylation activated mice using transgenic (TG) techniques. Lipopolysaccharide (LPS) was used to induce systemic inflammation in both TG and non-transgenic (NTG) mice. Serum cytokines were detected using a Mouse Cytokine Array, and the proportions of splenic NK, B and T cells were determined by using flow cytometry. We found that TG mice showed increased serum G-CSF, TNF RII and decreased serum TCA-3, CD30L, bFGF, IL-15 and MIG compared with NTG mice at baseline. Furthermore, serum cytokines in TG mice exhibited different responses to LPS compared to NTG mice. LPS up-regulated serum TNF RII, G-CSF, MCP-5, RANTES, KC, BLC, MIG and down-regulated IL-1b, IL-2, IL-3, IL-4, IL-5, IL-7, IL-10, IL-12p40, IL-15, IL-17, IFN-γ, TCA-3, Eotaxin-2, LIX, MCP-1, TNFα, GM-CSF in NTG mice, whereas LPS up-regulated G-CSF, MCP-5, RANTES, KC, BLC, MIG, ICAM-1, PF4, Eotaxin, CD30L, MIP-1a, TNFRI and down-regulated IL-1b, IL-3, LIX, MCP-1, TNFα, GM-CSF in TG mice. Data from flow cytometry indicated that LPS significantly reduced the percentages of NK and NKT cells in NTG mice, whereas UFMylation activation inhibited LPS-induced NKT cell decrease. The proportions of B cells, total CD4+ and total CD8+ T cells were comparable between TG and NTG mice in response to LPS treatment, whereas the percentages of CD4+CD69+ and CD8+CD69+T cells were lower in TG mice. These findings suggest that UFMylation may alter LPS-induced serum cytokine profile and participate in splenic T cell activation in vivo.

Inherent metabolic preferences differentially regulate the sensitivity of Th1 and Th2 cells to ribosome-inhibiting antibiotics.

Mitochondrial translation is essential to maintain mitochondrial function and energy production. Mutations in genes associated with mitochondrial translation cause several developmental disorders, and immune dysfunction is observed in many such patients. Besides genetic mutations, several antibiotics targeting bacterial ribosomes are well-established to inhibit mitochondrial translation. However, the effect of such antibiotics on different immune cells is not fully understood. Here, we addressed the differential effect of mitochondrial translation inhibition on different subsets of helper T cells (Th) of mice and humans. Inhibition of mitochondrial translation reduced the levels of mitochondrially encoded electron transport chain subunits without affecting their nuclear-encoded counterparts. As a result, mitochondrial oxygen consumption reduced dramatically, but mitochondrial mass was unaffected. Most importantly, we show that inhibition of mitochondrial translation induced apoptosis, specifically in Th2 cells. This increase in apoptosis was associated with higher expression of Bim and Puma, two activators of the intrinsic pathway of apoptosis. We propose that this difference in the sensitivity of Th1 and Th2 cells to mitochondrial translation inhibition reflects the intrinsic metabolic demands of these subtypes. Though Th1 and Th2 cells exhibit similar levels of oxidative phosphorylation, Th1 cells exhibit higher levels of aerobic glycolysis than Th2 cells. Moreover, Th1 cells are more sensitive to the inhibition of glycolysis, while higher concentrations of glycolysis inhibitor 2-deoxyglucose are required to induce cell death in the Th2 lineage. These observations reveal that selection of metabolic pathways for substrate utilization during differentiation of Th1 and Th2 lineages is a fundamental process conserved across species.

IgE and non-IgE food allergy: A review of immunological mechanisms.

Background: Food allergic (FA) conditions have been classified as immunoglobulin E (IgE) and non-IgE-mediated reactions that affect as many as 8% of young children and 2% of adults in Western countries, and their prevalence seems to be rising. Although the immunologic basis of IgE-mediated FA is well established, the mechanisms that govern non-IgE-mediated FA are not well understood and are marked by a paucity of comprehensive insights. Objective: The purpose of the present report is to examine the current classification and epidemiology of non-IgE-mediated FA, the latest immunologic mechanisms that underlie the three most commonly cited non-IgE FA conditions, viz., eosinophilic esophagitis, food protein-induced enterocolitis, and food protein-induced allergic proctocolitis, and explore what allergist/immunologists in practice should be aware of with regard to the condition. Methods: An extensive research was conducted in medical literature data bases by applying terms such as FA, non-IgE allergy, tolerance, unresponsiveness, cytokines, CD4+ T helper cell pathways, and key cytokine pathways involved in FA. Results: Current evidence now supports the view that immune dysregulation and cytokine-induced inflammation are the fundamental bases for both IgE- and non-IgE-mediated FA. The existing non-IgE-related FA literature is mostly characterized by a relative dearth of mechanistic information in contrast to IgE-mediated FA, in which the immunologic underpinnings as a T helper type 2 directed entity are well established. Although the need for future methodologic research and adherence to rigorous scientific protocols is essential, it is also necessary to acknowledge past contributions that have given much to our understanding of the condition. In the present report, a novel signature cytokine-based classification of IgE-mediated and non-IgE-mediated allergy is proposed that may offer a novel template for future research in the field of non-IgE-mediated FA. Conclusion: The present report provides an overview of the current classification and frequency of IgE- and non-IgE-mediated FAs, and offers insights and potential solutions to address lingering questions, particularly when concerning the latest immunologic mechanisms that underlie the pathogenesis of non-IgE-mediated FA. Although some progress has been made in recent years toward making diagnostic and treatment options available for these conditions, there still remain many lingering questions and concerns to be addressed, which can be fully understood by future research.

Autoantigen-specific CD4+ T cells acquire an exhausted phenotype and persist in human antigen-specific autoimmune diseases.

Pro-inflammatory autoantigen-specific CD4+ T helper (auto-Th) cells are central orchestrators of autoimmune diseases (AIDs). We aimed to characterize these cells in human AIDs with defined autoantigens by combining human leukocyte antigen (HLA)-tetramer-based and activation-based multidimensional ex vivo analyses. In aquaporin4-antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) patients, auto-Th cells expressed CD154, but proliferative capacity and pro-inflammatory cytokines were strongly reduced. Instead, exhaustion-associated co-inhibitory receptors were expressed together with FOXP3, the canonical regulatory T cell (Treg) transcription factor. Auto-Th cells responded in vitro to checkpoint inhibition and provided potent B cell help. Cells with the same exhaustion-like (ThEx) phenotype were identified in soluble liver antigen (SLA)-antibody-autoimmune hepatitis and BP180-antibody-positive bullous pemphigoid, AIDs of the liver and skin, respectively. While originally described in cancer and chronic infection, our data point to T cell exhaustion as a common mechanism of adaptation to chronic (self-)stimulation across AID types and link exhausted CD4+ T cells to humoral autoimmune responses, with implications for therapeutic targeting.

Inflammatory Biomarker Reduction With Fostemsavir Over 96 Weeks in Heavily Treatment-Experienced Adults With Multidrug-Resistant HIV-1 in the BRIGHTE Study.

Background: Fostemsavir, a first-in-class attachment inhibitor that binds to the viral envelope protein gp120, is approved for heavily treatment-experienced persons with HIV-1 with limited treatment options. We explored changes in immunologic and coagulopathy parameters in the BRIGHTE study: a phase 3 trial that evaluated fostemsavir plus optimized background therapy in heavily treatment-experienced adults with multidrug-resistant HIV-1. Methods: CD4+ T-cell count, CD4+/CD8+ ratio, soluble CD14, soluble CD163, and D-dimer levels were measured through 96 weeks in participants with 1 or 2 fully active antiretroviral agents available at screening. No formal statistical analyses were performed. Results: Among 272 participants, increases were observed from baseline to week 96 in CD4+ T-cell count (mean increase, +205 cells/mm3) and CD4+/CD8+ ratio (mean increase, +0.24). The proportion of observed participants with a CD4+/CD8+ ratio ≥0.45 increased from 9% (25/272) at baseline to 40% (85/213) at week 96. From baseline to week 96, we also observed trends toward decreases in the following (mean [SD] change): soluble CD14, -738.2 (981.8) µg/L; soluble CD163, -138.0 (193.4) µg/L; and D-dimer, -0.099 (0.521) mg/L fibrinogen-equivalent units. Decreases in biomarkers were generally observed among subgroups by baseline disease characteristics, virologic response, and CD4+ T-cell count. Conclusions: These data suggest that heavily treatment-experienced persons with multidrug-resistant HIV-1 treated with fostemsavir + optimized background therapy may have improvements in immune parameters, including markers of monocyte activation and coagulopathy. Clinical Trials Registration: NCT02362503 (ClinicalTrials.gov; https://clinicaltrials.gov/study/NCT02362503).

The phenotypic characteristics of polymorphonuclear neutrophils and their correlation with B cell and CD4+T cell subsets in thyroid-associated ophthalmopathy.

Introduction: Thyroid-associated ophthalmopathy (TAO) is considered to be an organ-specific autoimmune disease. Polymorphonuclear neutrophils (PMN) have been implicated in the pathogenesis of TAO. However, little is known about the role of PMN in the development of TAO, much less the relationship between PMN with B cells and CD4+T cells in TAO. Objective: This study aims to investigate the phenotypic characteristics of PMN and the relationship between PMN with CD4+T cell and B cell subsets in the pathogenesis of TAO. Methods: Blood routine information was collected from 135 TAO patients, 95 Grave's disease without TAO (GD) patients, and 116 normal controls (NC), while surface marker expression of PMN and the level of CD4+T cell and B cell subsets in peripheral blood from 40 TAO patients, 17 GD patients, and 45 NC was assessed by flow cytometry. Result: The level of PMN, CD62L+PMN, CD54+PMN, CD4+T cells, and Th17 cells displayed an increase in TAO patients than NC, while Treg cells were lower in the TAO group compared to NC. There was no statistical difference in Th1 and plasma cells among the groups. PMN were positively correlated with Th17 cells, but not the Th1, Treg, and plasma cells. Conclusion: In the present study, we found that the percentage of PMN and PMN subset cells was significantly higher in TAO than in NC, and PMN were positively correlated with Th17 cells. It suggests that PMN may be involved in the immunopathogenesis of TAO and modulate the Th17 cell response during this process.

Single-cell RNA sequencing reveals intratumoral heterogeneity and multicellular community in primary hepatocellular carcinoma underlying microvascular invasion.

Background: Microvascular invasion (MVI) is associated with an unfavorable prognosis and early recurrence of hepatocellular carcinoma (HCC), which is the crucial pathological hallmark of immunotherapy. While microvascular invasion (MVI) in hepatocellular carcinoma (HCC) currently lacks a detailed single-cell analysis of the tumor microenvironment (TME), it holds significant promise for immunotherapy using immune checkpoint inhibitors (ICI). Methods: We performed single-cell RNA sequencing (scRNA-seq) on 3 MVI positive (MVIP) and 14 MVI-negative (MVIN) tumor tissues, as well as their paired adjacent non-tumoral tissues. Results: We identified SPP1+ macrophages and CD4+ proliferative T cells as intertumoral populations critical for the formation of cold tumors and immunosuppressive environments in MVI-positive patients and verified their prognostic value in correlation with MVIP HCC patients. Additionally, we identified SPP1+ dominated interactions between SPP1+ macrophages and the immunosuppressive T population as contributors to MVI destruction and tumorigenesis. Conclusions: We provide a comprehensive single-cell atlas of HCC patients with MVI, shedding light on the immunosuppressive ecosystem and upregulated signaling associated with MVI. These findings demonstrate that intercellular mechanisms drive MVI and provide a potential immunotherapeutic target for HCC patients with HCC and underlying MVI.

Synergistic blockade of TIGIT and PD-L1 increases type-1 inflammation and improves parasite control during murine blood-stage Plasmodium yoelii non-lethal infection.

Pro-inflammatory immune responses are rapidly suppressed during blood-stage malaria but the molecular mechanisms driving this regulation are still incompletely understood. In this study, we show that the co-inhibitory receptors TIGIT and PD-1 are upregulated and co-expressed by antigen-specific CD4+ T cells (ovalbumin-specific OT-II cells) during non-lethal Plasmodium yoelii expressing ovalbumin (PyNL-OVA) blood-stage infection. Synergistic blockade of TIGIT and PD-L1, but not individual blockade of each receptor, during the early stages of infection significantly improved parasite control during the peak stages (days 10-15) of infection. Mechanistically, this protection was correlated with significantly increased plasma levels of IFN-γ, TNF, and IL-2, and an increase in the frequencies of IFN-γ-producing antigen-specific T-bet+ CD4+ T cells (OT-II cells), but not antigen-specific CD8+ T cells (OT-I cells), along with expansion of the splenic red pulp and monocyte-derived macrophage populations. Collectively, our study identifies a novel role for TIGIT in combination with the PD1-PD-L1 axis in regulating specific components of the pro-inflammatory immune response and restricting parasite control during the acute stages of blood-stage PyNL infection.

Augmented type 2 inflammatory response in allergic rhinitis patients experiencing systemic reactions to house dust mite subcutaneous immunotherapy.

BACKGROUND: Subcutaneous immunotherapy (SCIT) can induce systemic reactions (SRs) in certain patients, but the underlying mechanisms remain to be fully elucidated. METHODS: AR patients who were undergoing standardized HDM SCIT (Alutard, ALK) between 2018 and 2022 were screened. Those who experienced two consecutive SRs were included in the study group. A control group was established, matched 1:1 by gender, age, and disease duration with the study group, who did not experience SRs during SCIT. Clinical and immunological parameters were recorded and analyzed both before SCIT and after 1 year of treatment. RESULTS: A total of 161 patients were included, with 79 (49.07%) in the study group. The study group had a higher proportion of AR combined asthma (26.8% vs. 51.8%, p < 0.001) and higher levels of sIgE to HDM and HDM components (all p < .001). Serum IL-4 and IL-13 levels in the study group were higher than those in the control group (p < .05). The study group received a lower maintenance dosage of HDM extracts injections than control group due to SRs (50000SQ vs. 100000SQ, p < .05). After 1 year of SCIT, the VAS score, the lung function parameters of asthmatic patients over 14 years old significantly improved in both groups (all p < .05). After a 7-day exposure to 20 µg/mL HDM extracts, the percentages of Th1, Th17, Tfh10, and Th17.1 in PBMCs decreased, while the Tfh13 cells significantly increased in the study group (p < .05). CONCLUSION: The type 2 inflammatory response is augmented in HDM-induced AR patients who experienced SRs during SCIT. Despite this, SCIT remains effective in these patients when administered with low-dosage allergen extracts.

Stable and robust Xi and Y transcriptomes drive cell-type-specific autosomal and Xa responses in vivo and in vitro in four human cell types.

Recent in vitro studies of human sex chromosome aneuploidy showed that the Xi ("inactive" X) and Y chromosomes broadly modulate autosomal and Xa ("active" X) gene expression. We tested these findings in vivo. Linear modeling of CD4+ T cells and monocytes from individuals with one to three X chromosomes and zero to two Y chromosomes revealed 82 sex-chromosomal and 344 autosomal genes whose expression changed significantly with Xi and/or Y dosage in vivo. Changes in sex-chromosomal expression were remarkably constant in vivo and in vitro; autosomal responses to Xi and/or Y dosage were largely cell-type specific (∼2.6-fold more variation than sex-chromosomal responses). Targets of the sex-chromosomal transcription factors ZFX and ZFY accounted for a significant fraction of these autosomal responses both in vivo and in vitro. We conclude that the human Xi and Y transcriptomes are surprisingly robust and stable, yet they modulate autosomal and Xa genes in a cell-type-specific fashion.

The persistence of low CD4/CD8 ratio in chronic HIV-infection, despite ART suppression and normal CD4 levels, is associated with pre-therapy values of inflammation and thymic function.

BACKGROUND: Persistence of a low CD4/CD8 ratio is associated with an increased morbimortality in people living with HIV (PLWH) under effective antiretroviral therapy. We aimed to explore the immunological significance of a persistently low CD4/CD8 ratio, even despite normal CD4 levels, and assess whether these features vary from those associated to a low nadir-CD4, another well-established predictor of disease progression. METHODS: CD4-recovered PLWH were classified by CD4/CD8 ratio after three-years of ART (viral suppression, CD4≥500; R < 0.8, n = 24 and R > 1.2, n = 28). sj/ß-TRECs ratio and inflammatory-related markers were quantified. PBMCs were immunophenotyped by CyTOF and functionally characterized by ELISPOT. Subjects were also reclassified depending on nadir-CD4 (N ≤ 350/N > 350). RESULTS: R < 0.8 showed a differential inflammatory profile compared to R > 1.2 (increased ß2-microglobulin, D-dimers and IP-10 before ART). R < 0.8 presented lower baseline thymic function, being inversely correlated with post-ART inflammation. R < 0.8 at follow-up showed most alterations in CD8 subsets (increasing frequency and exhibiting a senescent phenotype [e.g., CD57+, CD95+]) and enhanced T-cell IFNγ/IL-2 secretion. However, comparing N ≤ 350 to N > 350, the main features were altered functional markers in CD4 T-cells, despite no differences in maturational subsets, together with a restricted T-cell cytokine secretion pattern. CONCLUSION: Persistence of low CD4/CD8 ratio in successfully-treated PLWH, with normal CD4 counts, is associated with baseline inflammation and low thymic function, and it features post-therapy alterations specific to CD8 T-cells. Differently, subjects recovered from low nadir-CD4 in this setting feature post-therapy alterations on CD4 T-cells. Hence, different mechanisms of disease progression could underlie these biomarkers, potentially requiring different clinical approaches.

mTOR aggravated CD4+ T cell pyroptosis by regulating the PPARγ-Nrf2 pathway in sepsis.

Sepsis is a systemic inflammatory response syndrome caused by a dysregulated host response to infection. CD4+T cell reduction is crucial to sepsis-induced immunosuppression. Pyroptosis, a programmed necrosis, is concerned with lymphocytopenia. Peroxisome proliferator-activated receptor gamma (PPARγ) regulated by upstream mTOR, exerts anti-pyroptosis effects. To investigate the potential effects of mTOR-PPARγ on sepsis-induced CD4+T cell depletion and the underlying mechanisms, we observed mTOR activation and pyroptosis with PPARγ-Nrf suppression through cecal ligation and puncture (CLP) sepsis mouse model. Further mechanism research used genetically modified mice with T cell-specific knockout mTOR or Tuberous Sclerosis Complex1 (TSC1). It revealed that mTOR mediated CD4 + T cell pyroptosis in septic mice by negatively regulating the PPARγ-Nrf2 signaling pathway. Taken together, mTOR-PPARγ-Nrf2 signaling mediated the CD4+ T cell pyroptosis in sepsis, contributing to CD4+T cell depletion and immunosuppression.

HIV-MTB Co-Infection Reduces CD4+ T Cells and Affects Granuloma Integrity.

Granuloma is a crucial pathological feature of tuberculosis (TB). The relationship between CD4+ T cells in both peripheral blood and granulomatous tissue, and the integrity of granulomas in Human Immunodeficiency Virus (HIV)-MTB co-infection, remains unexplored. This study collected biopsy specimens from 102 TB patients (53 with HIV-MTB co-infection and 49 only with TB). Hematoxylin and eosin (HE) staining and immunohistochemical staining were performed, followed by microscopic examination of the integrity of tuberculous granulomas. Through statistical analysis of peripheral blood CD4+ T cell counts, tissue CD4+ T cell proportion, and the integrity of granulomas, it was observed that HIV infection leads to poor formation of tuberculous granulomas. Peripheral blood CD4+ T cell counts were positively correlated with granuloma integrity, and there was a similar positive correlation between tissue CD4+ T cell proportions and granuloma integrity. Additionally, a positive correlation was found between peripheral blood CD4+ T cell counts and the proportion of CD4+ T cells in granuloma tissues. Therefore, HIV infection could impact the morphology and structure of tuberculous granulomas, with a reduced proportion of both peripheral blood and tissue CD4+ T lymphocytes.

The roles of CD4+ T cell help, sex, and dose in the induction of protective CD8+ T cells against a lethal poxvirus by mRNA-LNP vaccines.

The role of CD4+ T cells in the induction of protective CD8+ T cells by mRNA lipid nanoparticle (LNP) vaccines is unknown. We used B6 or Tlr9 -/- mice depleted or not of CD4+ T cells and LNP vaccines loaded with mRNAs encoding the ectromelia virus (ECTV) MHC class I H-2 Kb-restricted immunodominant CD8+ T cell epitope TSYKFESV (TSYKFESV mRNA-LNPs) or the ECTV EVM158 protein, which contains TSYKFESV (EVM-158 mRNA-LNPs). Following prime and boost with 10 µg of either vaccine, Kb-TSYKFESV-specific CD8+ T cells fully protected male and female mice from ECTV at 29 (both mRNA-LNPs) or 90 days (EVM158 mRNA-LNPs) post boost (dpb) independently of CD4+ T cells. However, at 29 dpb with 1 µg mRNA-LNPs, males had lower frequencies of Kb-TSYKFESV-specific CD8+ T cells and were much less well protected than females from ECTV, also independently of CD4+ T cells. At 90 dpb with 1 µg EVM158 mRNA-LNPs, the frequencies of Kb-TSYKFESV-specific CD8+ T cells in males and females were similar, and both were similarly partially protected from ECTV, independently of CD4+ T cells. Therefore, at optimal or suboptimal doses of mRNA-LNP vaccines, CD4+ T cell help is unnecessary to induce protective anti-poxvirus CD8+ T cells specific to a dominant epitope. At suboptimal doses, protection of males requires more time to develop.

Impact of "day 90" CD4+ T cells on clinical outcomes in children with relapsed/refractory acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: The severity of complications after hematopoietic stem cell transplantation (HSCT) is dictated by the degree of immune reconstitution. However, the connection between immune reconstitution and the prognosis of pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. Therefore, the aim of this study was to evaluate the impact of lymphocyte subsets in children diagnosed with refractory or relapsed acute myeloid leukemia (R/R-AML) after allo-HSCT. METHODS: We retrospectively investigated the prognosis and lymphocyte subsets at d 90 (D90) post-allo-HSCT in 130 children diagnosed with R/R-AML between September 2019 and October 2022 at the Children's Hospital of Soochow University. Lymphocyte subgroups were assessed by flow cytometric analysis on D90 and compared among human leukocyte antigen (HLA)-matched sibling donor HSCT (MSD) (n = 14), haploidentical donor HSCT (n = 94), and HLA-matched unrelated donor HSCT (n = 22) groups. The associations between the counts and frequencies of lymphocyte subgroups and prognosis were assessed. RESULTS: In the MSD group, CD4+ T cell frequency and count were the highest (P < 0.001). Among the examined lymphocyte subsets, a lower proportion of CD4+ T cells (<14.535 %) at D90 correlated with a higher risk of cytomegalovirus infection (P = 0.002). A higher CD4+ T cell count (>121.39/µL) at D90 after HSCT was the single predictor of a lower fatality risk across all lymphocyte subgroups (univariate: P = 0.038 cut-off: 121.39/µL; multivariate: P = 0.036). No association with relapse was observed. CONCLUSIONS: CD4+ T cell count may be used to identify pediatric patients with R/R-AML with a greater mortality risk early after HSCT.

CMPK2 Promotes CD4+ T Cell Activation and Apoptosis through Modulation of Mitochondrial Dysfunction in Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is a classic autoimmune disease characterized by abnormal autoantibodies, immune complex deposition, and tissue inflammation. Despite extensive research, the exact etiology and progression of SLE remain elusive. Cytidine/uridine monophosphate kinase 2 (CMPK2), a mitochondrial nucleoside monophosphate kinase, has garnered attention for its potential involvement in the development of various diseases, including SLE, where it has been observed to be dysregulated in affected individuals. However, the specific involvement of CMPK2 in the pathogenesis of SLE remains unclear. This study aims to clarify the expression level of CMPK2 in SLE CD4+ T cells and explore its impact on CD4+ T cells. The expression levels of the CMPK2 gene and the corresponding CMPK2 protein in CD4+ T cells of SLE patients were quantified using RT-qPCR and Western blot, respectively. Immunofluorescence and RT-qPCR were used to assess the mitochondrial function of SLE CD4+ T cells. Flow cytometry was used to assess CD4+ T cell activation and apoptosis levels. The impact of CMPK2 on CD4+ T cells was investigated by gene transfection experiment. We found that CMPK2 was significantly upregulated in SLE CD4+ T cells at both gene and protein levels. These cells demonstrated aberrant mitochondrial function, as evidenced by elevated mitochondrial reactive oxygen species (mtROS) levels, mitochondrial membrane potential, and mitochondrial DNA (mtDNA) copy number. Flow cytometry revealed a notable increase in both apoptosis and activation levels of CD4+ T cells in SLE patients. Gene transfection experiments showed that suppressing CMPK2 led to a significant improvement in these conditions. These findings suggest that CMPK2 may be involved in the pathogenesis of SLE by regulating mitochondrial dysfunction in CD4+ T cells and thus affecting CD4+ T cell activation and apoptosis. Our study may provide a new target for the treatment of SLE.

Metformin Restrains the Proliferation of CD4+ T Lymphocytes by Inducing Cell Cycle Arrest in Normo- and Hyperglycemic Conditions.

CD4+ T lymphocytes play a key role in the modulation of the immune response by orchestrating both effector and regulatory functions. The effect of metformin on the immunometabolism of CD4+ T lymphocytes has been scarcely studied, and its impact under high glucose conditions, particularly concerning effector responses and glucose metabolism, remains unknown. This study aims to evaluate the effect of metformin on the modulation of the effector functions and glucose metabolism of CD4+ T lymphocytes under normo- and hyperglycemic conditions. CD4+ T lymphocytes, obtained from peripheral blood from healthy volunteers, were anti-CD3/CD28-activated and cultured for 4 days with three concentrations of metformin (0.1 mM, 1 mM, and 5 mM) under normoglycemic (5.5 mM) and hyperglycemic (25 mM) conditions. Effector functions such as proliferation, cell count, cell cycle analysis, activation markers and cytokine secretion were analyzed by flow cytometry. Glucose uptake was determined using the 2-NBDG assay, and levels of glucose, lactate, and phosphofructokinase (PFK) activity were assessed by colorimetric assays. Metformin at 5 mM restrained the cell counts and proliferation of CD4+ T lymphocytes by arresting the cell cycle in the S/G2 phase at the beginning of the cell culture, without affecting cell activation, cytokine production, and glucose metabolism. In fact, CD69 expression and IL4 secretion by CD4+ T lymphocytes was higher in the presence of 5 mM than the untreated cells in both glucose conditions. Overall, metformin inhibited proliferation through mechanisms associated with cell cycle arrest, leading to an increase in the S/G2 phases at the expense of G1 in activated CD4+ T lymphocytes in normo- and hyperglycemic conditions. Despite the cell cycle arrest, activated CD4+ T lymphocytes remained metabolically, functionally, and phenotypically activated.

Elimination of GGTA1, CMAH, ß4GalNT2 and CIITA genes in pigs compromises human versus pig xenogeneic immune reactions.

BACKGROUND: Pig organ xenotransplantation is a potential solution for the severe organ shortage in clinic, while immunogenic genes need to be eliminated to improve the immune compatibility between humans and pigs. Current knockout strategies are mainly aimed at the genes causing hyperacute immune rejection (HAR) that occurs in the first few hours while adaptive immune reactions orchestrated by CD4 T cell thereafter also cause graft failure, in which process the MHC II molecule plays critical roles. METHODS: Thus, we generate a 4-gene (GGTA1, CMAH, ß4GalNT2, and CIITA) knockout pig by CRISPR/Cas9 and somatic cell nuclear transfer to compromise HAR and CD4 T cell reactions simultaneously. RESULTS: We successfully obtained 4KO piglets with deficiency in all alleles of genes, and at cellular and tissue levels. Additionally, the safety of our animals after gene editing was verified by using whole-genome sequencing and karyotyping. Piglets have survived for more than one year in the barrier, and also survived for more than 3 months in the conventional environment, suggesting that the piglets without MHC II can be raised in the barrier and then gradually mated in the conventional environment. CONCLUSIONS: 4KO piglets have lower immunogenicity, are safe in genomic level, and are easier to breed than the model with both MHC I and II deletion.